Reversible two-cycle internal-combustion engine.



H. T. BRUNS. REVERSIBLE TWO-GYGLE INTERNAL GOMBUSTION ENGINE.

APPLIGATION FILED DEC. 23, 1909.

Patented Aug. 26, 1913.

ya 2 P 7 q IIlW///// HANS THEODOB BRUNS, OF NUREMBERG', GERMANY.

REVERSIBLE TWO-CYCLE INTERNAL-COMBUSTION ENGINE.

Specification of Letters Patent.

Patented Au. 26,1913.

Application filed December 23, 1909. Serial No. 534,588.

To all whom it may concern Be it known that I, I'IANSTH. BRUNS, a subject of the King of Prussia, residing at Nuremberg, in the Kingdom of Bavaria and German Empire, have invented new and useful Improvements in and Relating to Reversible Two-Cycle Internal-Combustion Engines, of which the following is a specification.

In two-cycle motors which operate with exhaust ports controlled by the piston, the direction of rotation of the engine exerts no influence upon the exhaust. On the other hand on reversing the distributing shaft which actuates the fuel valves and the admission valves for the fresh air (scavenging air) the distributing shaft must be rotated through a certain angle. In accordance with the present invention this rotation of the distributing shaft takes place automatically as soon as the engine begins to run in the reverse direction upon the actuation of the starting mechanism. In order to attain this result the opening angles of the fuel valve and of the scavenging air valve are determined in such a manner and so arranged in the crank circle that when each of them is diminished by twice its angle of initial movement, two angles of equal magnitude remain. In order to illustrate this arrangement the crank circle of an engine of the novel kind is illustrated in the accompanying drawing in which Figure 1 is a diagram, showing the crank circle of my new type of engine; Fig. 2 a sectional view of the automatic reversing gear; Fig. 3 a plan view thereof; Fig. 4 a sectional View of a modification of the gear shown in Fig. 2 and Fig. 5 a plan view thereof.

In the drawing the arrow Q) indicates the direction of forward rotation.

T is the upper dead position of the piston and T the lower dead position. The injection of the fuel begins at A with the angle of initial movement v and continues until B. The total opening angle of the fuel valve is The exposure of the exhaust ports begins at the point C and lasts until D. At the point E, that is to say with the angle of initial movement 8, the scavenging valve opens and closes shortly after the piston has again covered the exhaust ports. Now when the total opening angle of the scavenging valve is the two angles e must be vertical and opposite angles as will appear from the following short explanations. 7

If the two angles a are halved the angles y which are formed by the lines of intersection must be 180 because in accordance with the hypothesis (1) Z:l808. Now

Y +C The value of C from (1) inserted in this gives y:5+180-8 or 7:180".

If however the opening angles of the scavenging-air and fuel valves are located symmetrically to a common diameter of the crank circle, it is obviously permissible to cause the engine to run in either direction if the distributing shaft is rotated through the angle 6 thereby displacing the dead points from T and T to T and T The corresponding direction of rotation is then 1". As shown in the drawing, the position of the opening angle of the scavenging-air valve relatively to the duration of the exhaust ports remains unaltered.

From what has been stated it appears that in multi-cylinder engines all the distributing members arranged on the distributing shaft may be fixed and that the distributing shaft may be rotated as a whole. In accordance with the present invention this rotation is effected automatically, for example by means of a loose clutch permitting of rotation of one half of the clutch relatively to the other by an angle equal to a. When the engine has run in one direction and is to be started in the opposite direct-ion, in the first place the distributing shaft remains stationary until the engine has rotated through the angle a whereupon it continues to act in the proper engagement. Unintentional relative displacement of the clutch members may be impeded by a braking device. The clutch itself may be constituted for example by an ordinary claw clutch with such play between the claws that it is possible for the two halves of the clutch to rotate relatively to each other through the desired angle. It is also possible to produce the rotation of the distributing shaft positively. If, for example, the distributing shaft is driven through worm wheels it is possible by displacing a wheel on a guide S to obtain the desired rotation before the starting of the engine.

In Figs. 2 and 3, a is the distributing shaft and o a crank shaft, or a countershaftoperatively connected therewith. The shaft a. provided with two distributing members, such as cam disks n and n. The distributing shaft (4 is driven by means of a pair of worm wheels 0, (Z; the wheel 0 is fixed on the distributing shaft a while the wheel (Z is displaceable on the shaft 7) but prevented from rotation by some appropriate means such as a .guide S, groove and feather or the like. The displacement of the wheel (Z is limited on both sides by stops f and g. Owing to the pitch of the worm teeth which permit of engagement between (2 and (Z, the worm wheel (Z (according as the shaft Z) rotates in one direction or the other) will automatically bear against either the stop f or the stop 9 and upon each reversal of the shaft 7) traverse the extent of this play automatically. During this displacement no transn'iission of the rotary movement from one shaft to the other takes place, so that upon each reversal of the shaft Z) automatic rotation relatively to the distributing shaft (4 takes place. The play of the worm wheel is calculated in such a manner that it corresponds exactly to the reversal angle. fit each reversal therefore the shaft 6 rotates alone until it has described the reversal angle, because the wheel (Z occupies this time to move the distance 6 and bear against the other stop. when this has taken place, the distributing shaft (4 is again driven. In order to avoid undesired automatic displacement of the wheel (Z on its parallel guide, it is provided with a pro longed hub 7: embraced by a divided ring 2'. This ring is pressed against the hub by means of springs 76 which bear against a suit able stop, the friction thus produced preventing undesired longitudinal displacement of the wheel (Z.

In the arrangement illustrated in Figs. 4c and 5, a again designates the distributing shaft, 0 and (Z the worm w ieels. The driving shaft is divided into two parts 5 and & connected one with the other by a claw clutch 1. The claws of the two clutch members are so arranged, as shown in Fig. 5, that the two clutch members and consequently the two lengths of shaft 7) and b are able to rotate relatively to each other through an angle a, the reversal angle. This rotation invariably takes place automatically when the driving length of shaft 6 alters its direction of rotation. Consequently at each reversal, relative displacement of the distributing shaft and of the crank shaft to the extent of the reversal angle takes place automatically. In order to avoid undesired rotation of the clutch members and consequently of the shafts, with this arrangement a spring 0 is pro vided and presses the two clutch members one against the other.

Having thus described my invention, I declare that what I claim as new and desire to secure by Letters Patent is In a reversible two-cycle engine, the combination with a single distributing shaft and the crank-shaft of a pair of wormwheels employed for driving said distributing shaft from said crankshaft, one of said worm-wheels being displaceably mounted on a guide, the rotation of the said distributing shaft being effected by the displacement of the said worm-wheel on the said guide.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HANS THEODOR BRUNS. lVitnesses BERNHARD GRAETZ, CARL GARZ.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

